Creasing device



Oct. 17, 1950 w. c. DAvis' ETAL CREASING DEVICE Filed March 8, 1946 2 Sheets-Sheet 1 .lllll. IIIIIL F-llll INVENTORS Mum/v 6. flaws. BY Mmnc: b4 h/aaaeom ATTORNEY Oct. 17, 1950 w. c. DAVIS ETAL CREASING DEVICE 2 Sheets-Sheet 2 Filed March 8, 1946 IIII'I I INVENTORS MAL/4M 6. flaws BY Mumme- N00220:!

ATTORNEY f'ate nteci bot. 1.7,

UNITED STATE 7 CREASING DEVICE William C. Davis, New Canaan, Conn., and Wallace H. Woodrow, Wilbraham, Mass., assignors to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware 7 Application March 8, 1946, Serial No. 652,838 g 1 Claim.

This invention relates to an apparatus for creasing sheets of plastic material. More particularly, this invention relates to an apparatus for testing the ability of plastic materials to withstand creasing operations without failure.

It is an object of this invention to provide apparatus for creasing plastic materials. A further object is to provide apparatus for testing the creasing properties of plastic materials.

These and other objects are accomplished according to the, invention described hereinafter with reference to a device presenting one embodiment of the invention and illustrated in the accompanying drawings.

' It is to be understood that the invention is not limitedin its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed in-the description is for the purpose of description and not of limitation.

In the drawings:

Fig. 1 is a side elevational view of a creasing device constructed in accordance with this invention. I

Fig. 2 is a top plan view of the same.

Fig; 3 is a sectional view taken on line 3-3 of Fig. 1. a

Fig. {l is an enlarged end elevational view of a creasing blade attached to the holder therefor, after-insertion of the heater and thermostat.

Fig. 5 is an enlarged end elevational view of a bar blade for creasing the plastic through an angle of 180.

Figs. 6-9 are enlargedside elevational views of four types of cams.

The apparatus illustratedin the accompanying drawings comprises a table or base In from which is suspended a drive shaft 1 I by means of hangers l2 having bearings 13 in which the drive shaft ll turns. Pulleys 14 mounted on drive shaft H are connected bymeans of belts (not shown) to a sourceof power (not shown) which may be an electric motor in combination with a reduction gear unit. V

On drive shaft I l are mounted cams it which, acting through cam followers ll, impart a reciprocating action to creasing blade l8. Creasing blade I8 is attached by means of screws l9 to holding plate 20 which, in turn, is fastened to guide plate 22 by cap screws 2|.

Guide plate 22 is welded, or otherwise firmly secured, to babbited bushings 23 which slide on guide posts 24. Attached to bushings 2.3 are arms 2 25 through which pass camfollowers I1. The positions of guide plate 22 and cam followers l'l relative to each other is maintained by set screws 26.

Attached to the table or base In by screws 28 is a plate 21 which covers a rectangular opening in the table. In the recess formed by the opening in the table covered from beneath, a slab of backing material 29 is placedwhich may vary from a solid steel bar to a soft resilient material such as sponge rubber, depending on the shape of the particular blade in use and the type of crease desired. As shown in Fig. 3; slab 29 is of sponge rubber. r When it is desired to increase the force of creasing blade 18, weights an- (shown in dotted lines) may be mounted on guide plate 22. These weights may .be of varying number and size depending on the load desired.

Creasing blade I8 has longitudinal passage 3| drilled therein to receive a tubular heater 32 and recess 33 to receive thermostat 34.v The heater has terminals 35 and 33 and the thermostat has terminals 31 and 38. Creasing blade [8 is separated from blade holder 28 by insulating material 39 which may be sheet asbestos or the like.

The heater terminal 36 and thermostat terminal 31 are connected together in series by insulated wire 40 shown in detail in Fig. 4. Heater terminal 35 andthermostat terminal 38 are connected to a suitable source of current by means of lead-in wires 4|. In order to provide for a more even temperature in the creasing blade, an auto-transformer (not shown) is preferably inserted between the heater and the source of current.

In'the operation of the apparatus illustrated in the accompanying drawings, a creasing blade l8 having a surface of the desired configuration is mounted on the blade holder 29 and the source of electrical current for heating the .blade connected to lead-in wires 4i. Weights 33 sufiicient in number and size to give the desired load are placed on guide plate 22. Cams [6 of such configuration as to give the desired rate of application of the load and dwell time of the load on the plastic are mounted on drive shaft II. A sheet of plastic material to be creased is placed beneath the creasing blade holder 20 upon an appropriate-backing material 29, the creasing blade holder being in a'raised position.

The proper cams, load and type of creasing blade having been installed, the creasing blade brought to the desired temperature, and the cams positioned on the upward stroke, the motor or other source of driving power for the drive shaft 3 is started. This causes the driving shaft H to turn and operating through the cam l6 and cam follower l7 causes the creasing blade i8 to rise and fall in successive cycles. The blade on the down stroke creases the plastic sheet which may be shifted thereafter during the upward stroke ing blade is so constructed that the sides of the blade are at the desired angle to each other, e. g. 60, and the forward edge is somewhat blunted so as not to cut the plastic.

In creasing plastic sheets through an angle of 180, the backing material comprises a bar of a hard material such as a steel bar having a flat pressing surface. The plastic sheet is looped back on itself to present a wide loop beneath the blade.

As pointed out above, cams of varying configuration may be used to vary the rate of application of the load. Thus, a cam of the type illustrated by Fig. 6 is used when a moderate rate of load application is desired. When the rate of application of load resulting from a free I fall is desired, a cam of the type illustrated in Fig. 7 is used. Cams having configurations resulting in a free fall, but long dwell periods on the plastic are illustrated in Figs. 8 and 9.

In addition to the" use of the device of the invention for testing the creasing properties of plastic materials, it is also admirably adapted for the manufacture of creased articles, such as lampshade material. By, virtue of the combination of means for controlling the temperature of the creasing blade, the load, the rate of application of the load and the dwell time of the creasingrblade on the plastic, it is possible to impart a. desired crease or fold on a wide variety of plastic materials without injury thereto.

In certain cases it may be desirable to apply a stream of cold air to the plastic. immediately after removal of the creasing blade to cool the 'plastic and set the'crease, particularly when a high temperature creasing blade is required.

The device of the invention may be used to crease sheets made from various types of plastic material, for example, those made from cellulose derivatives such as cellulose acetate, cellulose nitrate, cellulose aceto-butyrate, ethyl cellulose; vinyl resins such as polyvinyl chloride, vinyl chloride-vinyl acetate and similar copolymers, vinyl chloride-methyl acrylate copolymers, esters of acrylic and methacrylic acid and the like.

Sheets of diiferent thicknesses may be creased with the device of the invention, for example, sheets having a thickness of as little as 0002-0005 inch up to 0.01 inch or more with suitable adjustment of the load, temperature, etc.

It is to be understood that the description of this invention is illustrative thereof and that variations may be made within the scope of the invention as defined in the appended claim.

What is claimed is:

In a creasing device for plastic materials, in combination, a base, a drive shaft suspended from said base, cams mounted on said shaft and spaced inwardly. from each extremity of said shaft, cam followers in contact with said cams, extension members attached to said cam followers and passing through said base, arms adjustably attachable to said extension members above said base, a guide plate, bushings attached to and intermediate said. arms and said guide plate, posts attached at right angles. to said base and passing through saidbushings, a blade mounted on said plate so that the edge of said blade is directed at right angles to said base, detachable weights on said plate to control the force of said blade, an electrical heater and thermostat having leads for connection to a source of electrical current Within said blade and a backing material on said base for supporting the plastic and receiving the action of said blade.

WILLIAM C. DAVIS. WALLACE I-I. WOO-DROW.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 161,737 Beardslee Apr. 6, 1875 914,816 Dunton Mar. 9, 1909 1,013,832 Allen Jan. 3, 1912 1,429,481 Ayers, Jr Sept. 16, 1922 1,604,141 Amsler Oct. 26, 1926 1,646,195 German Oct. 18, 1927 2,045,548 Dillon et al June 23, 1936 2,396,620 Taxwood Mar. 12, 1946 

